This item represents the weighted average life in years of debt securities.

No definition available.

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Data Type:	xbrli:durationItemType
Balance Type:	na
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- Definition

Debt Securities Weighted Average Yield To Maturity

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Remaining period of expected liquidation by investee of underlying asset of investment measured at net asset value per share or unit. In 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
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-Subparagraph (e)
-Publisher FASB
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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
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-Paragraph 4
-Subparagraph (b)(3)
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-URI https://asc.fasb.org/1943274/2147481139/470-20-50-4

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
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Balance Type:	credit
Period Type:	instant

- Definition

Fair value portion of other liabilities.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2E
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-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

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Period Type:	instant

- Definition

Amount of long-term investments classified as other.

+ References

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-Topic 944
-SubTopic 210
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of unrealized gain (loss) on investment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (b)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

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FAIR VALUE MEASUREMENTS - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	$ 4,172,451		$ 4,172,451		$ 3,515,566
Other liabilities	3,457		3,457		2,742
Debt	1,935,928		1,935,928		1,958,655
Long-term debt, fair value	1,900,000		1,900,000		1,900,000
Net Investment Income \| Term Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net unrealized (losses) gains recognized in earnings	208,500	$ 20,200	197,100	$ 100,600
Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	4,172,451		4,172,451		3,515,566
Significant Other Observable Inputs (Level 2) \| Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	2,044,080		2,044,080		1,942,199
Significant Other Observable Inputs (Level 2) \| Fair Value, Measurements, Recurring \| Direct private equity investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	148,005		148,005		0
Significant Other Observable Inputs (Level 2) \| Fair Value, Measurements, Recurring \| Term Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	0		0		0
Significant Other Observable Inputs (Level 2) \| Quoted Prices \| Fair Value, Measurements, Recurring \| Direct private equity investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	148,000		148,000
Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	145,609		145,609		157,563
Other liabilities	497		497		515
Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring \| Direct private equity investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	51,034		51,034		59,905
Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring \| Term Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	94,575		94,575		97,658
Significant Unobservable Inputs (Level 3) \| Internal valuation model \| Fair Value, Measurements, Recurring \| Assumed and ceded (re)insurance contracts, group two
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other liabilities	497		497		515
Significant Unobservable Inputs (Level 3) \| Internal valuation model \| Fair Value, Measurements, Recurring \| Direct private equity investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	51,034		51,034		59,905
Significant Unobservable Inputs (Level 3) \| Internal valuation model \| Fair Value, Measurements, Recurring \| Term Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other investments	$ 94,600		$ 94,600		$ 97,700
U.S. Treasuries
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average effective yield	3.70%		3.70%		4.10%
Corporate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average effective yield	5.10%		5.10%		5.70%
Agencies
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average effective yield	4.50%		4.50%		4.60%
Non-U.S. Government
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average effective yield	4.10%		4.10%		4.40%
Residential Mortgage-backed
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average effective yield	4.80%		4.80%		5.10%
Weighted average life			7 years 3 months 18 days		7 years 8 months 12 days
Commercial Mortgage-backed
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average effective yield	5.80%		5.80%		8.80%
Weighted average life			3 years 9 months 18 days		2 years 2 months 12 days
Asset-backed
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average effective yield	6.20%		6.20%		7.00%
Weighted average life			4 years 6 months		3 years 10 months 24 days
Short Term Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average effective yield	4.20%		4.20%		5.30%
Other Short Term Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average effective yield	4.80%		4.80%		5.30%
Private Credit Funds \| Minimum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liquidation period for fund assets			5 years
Private Credit Funds \| Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liquidation period for fund assets			10 years
Direct private equity investments \| Minimum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liquidation period for fund assets			5 years
Direct private equity investments \| Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liquidation period for fund assets			10 years